Albendazole (Albenza, Valbazen)

By | 2013-06-08

Antiparasitic

Highlights Of Prescribing Information

Broad spectrum against a variety of nematodes, cestodes & protozoa; labeled for cattle & sheep (suspension only)

Contraindicated with hepatic failure, pregnancy, lactating dairy cattle

May cause GI effects (including hepatic dysfunction) & rarely blood dyscrasias (aplastic anemia)

Do not use in pigeons, doves or crias

What Is Albendazole Used For?

Albendazole is labeled for the following endoparasites of cattle (not lactating): Ostertagia ostertagi, Haemonchus spp., Trichostrongylus spp., Nematodius spp., Cooperia spp., Bunostomum phlebotomum, Oesphagostomum spp., Dictacaulus vivaparus (adult and 4th stage larva), Fasciola hepatica (adults), and Moniezia spp.

In sheep, albendazole is approved for treating the following endoparasites: Ostertagia circumcincta, Marshallagia marshalli, Haemonchus contortus, Trichostrongylus spp., Nematodius spp., Cooperia spp., Oesphagostomum spp., Chihertia ovina, Dictacaulus filaria, Fasciola hepatica, Fascioides magna, Moniezia expansa, and Thysanosoma actinoides.

Albendazole is also used (extra-label) in small mammals, goats and swine for endoparasite control.

In cats, albendazole has been used to treat Paragonimus kellicotti infections. In dogs and cats, albendazole has been used to treat capillariasis. In dogs, albendazole has been used to treat Filaroides infections. It has been used for treating giardia infections in small animals, but concerns about bone marrow toxicity have diminished enthusiasm for the drug’s use.

Pharmacology/Actions

Benzimidazole antiparasitic agents have a broad spectrum of activity against a variety of pathogenic internal parasites. In susceptible parasites, their mechanism of action is believed due to disrupting intracellular microtubular transport systems by binding selectively and damaging tubulin, preventing tubulin polymerization, and inhibiting microtubule formation. Benzimidazoles also act at higher concentrations to disrupt metabolic pathways within the helminth, and inhibit metabolic enzymes, including malate dehydrogenase and fumarate reductase.

Pharmacokinetics

Pharmacokinetic data for albendazole in cattle, dogs and cats was not located. The drug is thought better absorbed orally than other benzimidazoles. Approximately 47% of an oral dose was recovered (as metabolites) in the urine over a 9-day period.

After oral dosing in sheep, the parent compound was either not detectable or only transiently detectable in plasma due to a very rapid first-pass effect. The active metabolites, albendazole sulphoxide and albendazole sulfone, reached peak plasma concentrations 20 hours after dosing.

Before you take Albendazole

Contraindications / Precautions / Warnings

The drug is not approved for use in lactating dairy cattle. The manufacturer recommends not administering to female cattle during the first 45 days of pregnancy or for 45 days after removal of bulls. In sheep, it should not be administered to ewes during the first 30 days of pregnancy or for 30 days after removal of rams.

Pigeons and doves may be susceptible to albendazole and fenbendazole toxicity (intestinal crypt epithelial necrosis and bone marrow hypoplasia).

Nine alpaca crias receiving albendazole at dosages from 33-100 mg/kg/day once daily for 4 consecutive days developed neutropenia and severe watery diarrhea. All required treatment and 7 of 9 animals treated died or were euthanized secondary to sepsis or multiple organ failure. ()

In humans, caution is recommended for use in patients with liver or hematologic diseases.

Albendazole was implicated as being an oncogen in 1984, but subsequent studies were unable to demonstrate any oncogenic or carcinogenic activity of the drug.

Adverse Effects

Albendazole is tolerated without significant adverse effects when dosed in cattle or sheep at recommended dosages.

Dogs treated at 50 mg/kg twice daily may develop anorexia. Cats may exhibit clinical signs of mild lethargy, depression, anorexia, and resistance to receiving the medication when albendazole is used to treat Paragonimus. Albendazole has been implicated in causing aplastic anemia in dogs, cats, and humans.

Reproductive / Nursing Safety

Albendazole has been associated with teratogenic and embryotoxic effects in rats, rabbits and sheep when given early in pregnancy. The manufacturer recommends not administering to female cattle during the first 45 days of pregnancy or for 45 days after removal of bulls. In sheep, it should not be administered to ewes during the first 30 days of pregnancy or for 30 days after removal of rams.

In humans, the FDA categorizes this drug as category C for use during pregnancy (Animal studies have shown an adverse effect on the fetus, hut there are no adequate studies in humans; or there are no animal reproduction studies and no adequate studies in humans.)

Safety during nursing has not been established.

Overdosage/Toxicity

Doses of 300 mg/kg (30X recommended) and 200 mg/kg (20X) have caused death in cattle and sheep, respectively. Doses of 45 mg/ kg (4.5X those recommended) did not cause any adverse effects in cattle tested. Cats receiving 100 mg/kg/day for 14-21 days showed signs of weight loss, neutropenia and mental dullness.

How to use Albendazole

Albendazole dosage for dogs:

For Filaroides hirthi infections:

a) 50 mg/kg q12h PO for 5 days; repeat in 21 days. Clinical signs may suddenly worsen during therapy, presumably due to a reaction to worm death. ()

b) 25 mg/kg PO q12h for 5 days; may repeat in 2 weeks (also for Oslerus osleri) ()

For Filaroides osleri (also known as Oslerus osleri) infections:

a) 9.5 mg/kg for 55 days or 25 mg/kg PO twice daily for 5 days.

Repeat therapy in 2 weeks. ()

For Capillaria plica:

a) 50 mg/kg q12h for 10-14 days. May cause anorexia. ()

For Paragonimus kellicotti:

a) 50 mg/kg PO per day for 21 days ()

b) 30 mg/kg once daily for 12 days ()

c) 25 mg/kg PO q12h for 14 days ()

For Giardia:

a) 25 mg/kg PO q12h for 4 doses ()

b) 25 mg/kg PO twice daily for 5 days ()

c) 25 mg/kg PO twice daily for 2- 5 days ()

For Leishmaniasis:

a) 10 mg/kg PO once daily for 30 days or 5 mg/kg PO q6h for 60 days ()

Albendazole dosage for cats:

For Paragonimus kellicotti:

a) 50 mg/kg PO per day for 21 days ()

b) 25 mg/kg PO q12h for 10-21 days ()

c) 30 mg/kg once a day for 6 days ()

d) 25 mg/kg PO q12h for 14 days ()

For Giardia:

a) 25 mg/kg PO twice daily for 5 days ()

b) 25 mg/kg PO q12h for 3-5 days; may cause bone marrow suppression in dogs and cats. ()

For treatment of liver flukes (Platynosum or Opisthorchiidae families):

a) 50 mg/kg PO once daily until ova are gone ()

Albendazole dosage for rabbits, rodents, and small mammals:

a) Rabbits: For Encephalitozoon phacoclastic uveitis: 30 mg/kg PO once daily for 30 days, then 15 mg/kg PO once daily for 30 days ()

b) Chinchillas: For Giardia: 50-100 mg/kg PO once a day for 3 days ()

Albendazole dosage for cattle:

For susceptible parasites:

a) 10 mg/kg PO (Labeled directions; Valbazen — Pfizer)

b) 7.5 mg/kg PO; 15 mg/kg PO for adult liver flukes ()

c) For adult liver flukes: 10 mg/kg PO; best used in fall when the majority are adults (little or no efficacy against immature forms). A second treatment in winter maybe beneficial. ()

d) For gastrointestinal cestodes: 10 mg/kg PO ()

Albendazole dosage for swine:

For susceptible parasites:

a) 5-10 mg/kg PO ()

Albendazole dosage for sheep and goats:

For susceptible parasites:

a) 7.5 mg/kg PO (0.75 mL of the suspension per 25 lb. body weight). (Labeled directions; Valbazen Suspension — Pfizer)

b) 7.5 mg/kg PO; 15 mg/kg PO for adult liver flukes ()

c) For adult liver flukes in sheep: 7.6 mg/kg ()

d) For treatment of nematodes in sheep: 3 mL of suspension per 100 lbs of body weight PO ()

Albendazole dosage for birds:

a) Ratites: Using the suspension: 1 mL/22 kg of body weight twice daily for 3 days; repeat in 2 weeks. Has efficacy against flagellate parasites and tapeworms. ()

Monitoring

■ Efficacy

■ Adverse effects if used in non-approved species or at dosages higher than recommended

■ Consider monitoring CBC’s and liver enzymes (q4-6 weeks) if treating long-term (>1 month)

Client Information

■ Shake well before administering

■ Contact veterinarian if adverse effects occur (e.g., vomiting, diarrhea, yellowish sclera/mucous membranes or skin)

Chemistry / Synonyms

A benzimidazole anthelmintic structurally related to mebendazole, albendazole has a molecular weight of 265. It is insoluble in water and soluble in alcohol.

Albendazole may also be known as. Albendazole may also be known by these synonyms: albendazolum, SKF-62979, Valbazen or Albenza; many other trade names are available.

Storage / Stability

Albendazole suspension should be stored at room temperature (15-30°C); protect from freezing. Shake well before using. Albendazole paste should be stored at controlled room temperature (15-30°C); protect from freezing.

Dosage Forms/ Regulatory Status

Veterinary-Labeled Products:

Albendazole Suspension: 113.6 mg/mL (11.36%) in 500 mL, 1 liter, 5 liters; Valbazen Suspension (Pfizer); (OTC). Approved for use in cattle (not female cattle during first 45 days of pregnancy or for 45 days after removal of bulls, or of breeding age) and sheep (do not administer to ewes during the first 30 days of pregnancy or for 30 days after removal of rams). Slaughter withdrawal for cattle = 27 days at labeled doses. Slaughter withdrawal for sheep = 7 days at labeled dose. Since milk withdrawal time has not been established, do not use in female dairy cattle of breeding age.)

Albendazole Paste: 30% in 205 g (7.2 oz); Valbazen (Pfizer); (OTC). Approved for use in cattle (not female cattle during first 45 days of pregnancy or for 45 days after removal of bulls or of breeding age). Slaughter withdrawal = 27 days at labeled doses. Since withdrawal time in milk has not been established, do not use in female dairy cattle of breeding age.

Human-Labeled Products:

Albendazole Tablets: 200 mg; Albenza (SmithKline Beecham); (Rx)